Former Rep. Ron Paul, R-Texas, endorsed Rep. Paul Broun, R-Ga., in what is shaping up to be Republicans' widest and most unpredictable Senate primary.

"If we're going to restore our Constitution and put our nation back on the path to prosperity, we must elect principled conservatives who will fight in Washington," Paul, a former presidential candidate with deep tea party support, said in an email Thursday. "Paul Broun will continue fighting, and that's why I endorsed his candidacy for U.S. Senate in Georgia."

Broun is one of many House members from Georgia seeking the seat of retiring GOP Sen. Saxby Chambliss. On the GOP side, Broun and fellow Rep. Phil Gingrey are already in the race. Reps. Tom Price and Jack Kingston are also considering bids.